Treatment of cotton fabrics with urea-alkali-zincate solution



Patented Oct. 24, 1950 TREATMENT OF COTTON FABRICS WITH UREA-ALKALL-ZINCATE SOLUTION Charles L. Mantell, Manhasset, and Oscar K. Helm, Woodside, N. Y., assignors to United Merchants & Manufacturers, Inc.,

Wilmington,

Del., a corporation of Delaware No Drawing. Application May 10, 1949, Serial No. 92,511

20 Claims. (01. 8-116.2)

This invention relates to the treatment of cotton fabrics and has for its primary object a method of modifying the normal characteristics of woven or knitted cotton cloth 'to the end of producing a fabric of enhanced value and utility, the method requiring no complicated or special equipment for its practice and being otherwise economical to carry out. As hereinafter described in greater detail, the invention contemplates the treatment of the fabric with a solution which, in more or less noticeable degree according to the character of the fabric and the methodemployed, produces some or all of the effects of modifying the shrinkage characteristics of the fabric, eliminating fuzz, and rendering the fabric stiffer and somewhat translucent.

The invention essentially comprises a process of treating cotton fabric with a solution containing caustic zincate and urea, hereinafter referred to as the treating solution, there being obtained a fabric having, among other effects, appreciably modified shrinkage characteristics; that is, it shows a substantially reduced shrinkage by comparison with the normal shrinkage of the untreated fabric, considering such normal shrinkage to be the initial wash shrinkage. In addition, the treated fabric has a more clearcut and attractive appearance. Thus, when the untreated fabric is held up to the light and examined, 1. e., held between the light and the eye, it presents a misty appearance due to the lack of sharp definition of the warp and, weft thread outlines which results from the fuzz on the threads. This characteristic is particularly evident when such fabrics are used, for example, as curtains. It has been found, according to this invention, that if the fabric is treated as described, its appearance is, quite radically changed. When the fabric so treated is held up to the light and examined as before, it is observed that the threads are sharply outlined, there being substantially no evidence of fuzz. It has also been observed in some instances that, notwithstanding the sharpening of the outlines of the thread the body of ea h thread assumes a somewhat translucent character. As will be understood. these last mentioned effects will each be more or less noticeable and of varying practical consequence depending on .the character of the fabric and the use to which it is put;

2 but, for convenience, they may be described as bringing about a clarification of the fabric.

It has further been observed that the treated fabric tends to become stiffer by comparison with the untreated fabric. Stiffness is a desirable characteristic in certain materials, for example in curtain and table goods and in certain types of dresses and blouses, e. g., lawns and organdies.

Besides the above-mentioned solution treating process, the invention also comprises the combination therewith of one or more other steps as modifications of the process. Such modified processes may comprise (1) a preliminary chemical degradation step followed by the solution treating step; and (2) a preliminary chemical degradation step, the solution treating step, and treatment with a special stiffening liquor. While the effects achieved by means of the solution treating process are noteworthy in themselves, it has been found that additional advantages may be realized by means of the modified processes.

Each of these processes will be hereinafter described in relation to the treatment of an open weave cotton fabric, but it is to be understood, of course, that the advantages of the invention may be obtained with cotton fabrics in general.

As described, the treating solution is composed of caustic zincate and urea. It may be prepared by mixing together an aqueous solution of .urea

and an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate: or by adding zinc oxide to an aqueous solution of an alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, sodium zincate and potassium zincate respectively being formed, and then incorporating the urea. It is to be understood that in referring to the zinc oxide content of the solution it is intended to include the oxide added as such or as comprised in the alkali metal zincate added to the solution or formed therein. Compounds which, when added to a caustic zincate solution, hydrolyze to form urea, may be used in making up the solvent. Such compounds may include, for example, cyanamide, guanidine, guanylurea, etc. In the premises, it will be under- .stood that the term urea" as used herein is intended to include urea per se and also compounds which produce urea as in the foregoing manner.

The amount of urea may be varied from about 2 to about 20% by weight. At concentrations below this range, the soluflon has decreased effects, while at concentrations above 20%, no worthwhile improvements result. Zinc oxide, whether added as such or in the form of the zincate, may be present in amounts ranging from about 2 to about by weight, calculated as zinc oxide; while the caustic may be varied about 28% by weight or more, although the use of higher concentrations of caustic generally does not justify the added expense involved. If sodium hydroxide is employed as the caustic, a preferred concentration is from about 6 to about for potassium hydroxide a preferred range is from about 8 to about 28%. As in the case of urea, the effects are by going below the minimum concentrations of the latter materials; above the maximum concentrations given, there is no worthwhile improvement in results. A preferred solution is one containing about 10% urea, about 6% zinc oxide, and about 12% caustic.

Application of the solution to the fabric is done by simply pouring it on the fabric, although usually it is better to rub it on, either manually or by means of knives or doctor blades. Mangle equipment such as padders or quetches are useful for this purpose, as is also pressure equipment like rollers. Jigs and rolls are likewise suitable. The fabric may or may not be under tension during the application of the solution. Preferably it is not. The time of treatment is not critical and may range from about 1 second up to 24 hours or more, and may conveniently be in the range of 1 second to 1 hour. The treating temperature used is generally room temperature, although, of course, higher and lower temperatures, say from the freezing oint to 120 F., may be employed. After treating, the solution may be allowed to dry on the fabric or not, as desired. The goods then may be neutralized, rinsed and dried; or neutralized and dried; or washed and dried. Moreover, in any sequence of these steps and at any stage thereof, the goods in process may or may not be under tension. Thus after the treating solution has been applied, the following alternative procedures or variations may be employed. 1. Dry under tension, neutralize, rinse, dry. 2. Dry under tension, neutralize, dry. 3. Dry under tension, wash, dry. 4. Dry without tension, neutralize, rinse, dry. 5. Dry without tension, neutralize, dry. 6. Dry without tension, wash, dry. '1. Neutralize, rinse, 'dry. 8. Neutralize, dry. 9. Wash, dry. In further variations of the procedure, as indicated, the neutralizing, rinsing, washing and final drying steps may each be done while the material is in either a stretched or unstretched condition. The preferred method is as follows: Dry under tension, for example on a tenter or drying can, neutralize with dilute acid and rinse with water, the neutralization and rinslng being done while the fabric is in an unstretched condition, and frame dry.

The following example illustrates the improvement with respect to fabric shrinkage obtainable by the invention.

Example 1 Cotton marquisette containing starch was held under moderate tension on a frame and treated at room temperature with an aqueous solution containing 10% urea, 4.5% zinc oxide and 10% caustic soda. The solution was poured over the cloth for about two minutes and then the cloth was washed with colt water and 1% acetic acid from about 6 to to remove the alkali and zinc.

The goods were further washed with cold water until neutral and dried in warm air at about 100 F. Another sample of marquisette was treated the same way after first removing the starch. The results follow:

The shrinkages reported were obtained according to A. S. T. M. D43'I-36. By the term cotton marquisette containing starc is meant either a fabric in its grey stage from which the starch used as a sizing on the yarn has not been removed, or a semi-finished fabric to which starch has been applied, or a finished fabric to which the starch has been applied as a finish. In addition, unsized, desized, and unfinished goods may be treated in the manner described.

If the treating solution is not washed from the cloth but dried on instead, as is presently preferred, a lower shrinkage effect may be realized. The following example illustrates this variation in procedure:

Example 2 Cotton marquisette that had been kier-boiled and partially mercerized according to conventional practice was subjected to treatment with the solution employed in Example 1. One sample of cloth was treated with the solution for about one minute at 25 C., and then washed and dried as above described. A second sample was treated with solution for about one minute at 25 C., then warmed at 260 F. until the cloth was just dry, and thereafter washed and dried as the first sample. The first sample showed a warp shrinkage of 10.3% and a filling shrinkage of 7.7%; the second showed a warp shrinkage of 6.6% and a filling shrinkage of 7.4%. Shrinkage was determined according to A. S. T.- M. D437-36. The results obtained with the second sample were duplicated with a solution of somewhat different composition, namely, 2.6% zinc oxide, 7.4% caustic, and 5% urea, the procedure being otherwise the same. It was further noticed that when the solution was dried on the cloth, better stiffness was obtained.

In each of the foregoing examples the visual characteristics of the treated cloth are appreciably altered. By comparison with the original material, the treated cloth has a cleaner thread outline and an overall translucent appearance. These effects are produced in addition to the effects of shrinkage control or dimensional stability and stiffness. By modifying the foregoin process it has been found that the latter eflects may be favorably increased.

Other examples are as follows:

Example 3 Samples of a leno weave cotton marquisette,

1. which previously had been mercerized, kier-boiled pears below. The solutions were poured over the stretched fabrics for one minute. the fabrics dried at 240 F.. then removed from the stretchers and ,neutralized with dilute sulfuric acid, rinsed with cold water, refrained and dried at 240 F. A conunder tension, given an acid washiollowed by a water rinse, and dried on a frame. No difliculty was experienced in framing these samples to their original width. The results are as follows:

trol sample was treated with water instead of 5 solution. Shrinkage, tensile strength (warp) and Time shrink, stiffness data were then obtained on the samples. 8mm 3 :5 f The results are as follows: 01 my, m Emmi! Moist Warp Filling l0 BM i. a. Twins Com 1 an 4.1 4.5 24.x wt 0 1 I 13? at? 3'2 NaOH ZnO Urea Warp ,22

l Treated with water, not solution. a m le 0 s 2 2 ii- 25.4 0.50 m p 8 2 2;; h g3 2'; 2 Samples of mercerized, kier boiled and bleached 20 80 x 80 cotton print cloth were padded in the i; 3 ,3 3;; 22 2 fi unstretched condition with the solution of Ex- 12 6 20 ample lfor various times. The samples were then 0mm"! dried on a frame, taken off the frame and neutralized with acid, rinsed. and lnally dried on Shrinkages were determined as in Example 2. 25 a frame The results are as mnows' and stifiness was determined by the Peirce heart loop method. Tensile strength was found by a Sh k Scott inclined plane tester on strips 38 ends wide 5mm ..?..i........ m m Tensile 585 5 with one inch between clamps. oi Solution strength cient It will be seen from the above example that all 30 warp Filling v of the treated fabrics show better shrinkage and stiflness characteristics than the untreated fabric. 1 3 fl," H'; I. 40 2 10 3.1 3.4 64.4 ass Example 4 Control 110 6.1 6.9 56.1 0.58

In the following example, the time of appli- 35 Treated with not 801mm cation of the solution to a cotton marquisette In a modification of the foregoing solution fabric of the type described in Example 3 was treating process the clbth is subjected to the varied from 1 Se to 24 In each 0856- action of a chemical degradation agent and then following contact of the solution with the fabric, 0 treated with the solution as described. The

the latter was dried under tension, after which the fabric was washed and dried. The solution used was the same for all samples and contained 12% caustic, 6% zinc oxide and 10% urea. In some cases the washing procedure and the final drying step were varied.

ject of the degradation step is to render the cloth more susceptible to the action of the solution, but care must be exercised to limit the amount of degradation. To this end the strength of the agent and the time and temperature of its application are carefully controlled.

Solution Application Shrinkage D ing under Tensile 8mm! Tensioning washing ension- Strength Sample Time during Warp Filling Treatment Per Per Pound: cent cm! Acid wash Yes 3. 8 6. 4 28. 8 l. 59

pluswater rinse. Like 1 5. 3 7. 8 36. 3 l. 80 do 4. 0 8. 0 34. 0 0. 9i dn 4. 3 7. 3 32. 5 l. 08 do 4.2 6.2 32.6 227 dn dn 3.3 5. 1 38.3 1.24 -.do No-Dried Flat... 1. 6 2. 8 28.0 i. 69 Hot Water. Yes 3. 2 8. 9 28. 8 0. 72 Ire I do 10. 1 I). 9 30. 5 0.51

l Treated with water, not solution. 1 But kept under tension for 24 hrs. while moist with solution.

Example 5 In the following tests, cotton marquisette, similar to that of Examples 3 and 4, after the padding of solution (the same solution as in the preceding example) on the same in unstretched condition, was allowed to remain wet with the solu tion for various periods of time and while still unstretched. Thereafter the fabric was dried other alkali metal and alkaline earth metal peroxides, and sulfuric acid. Sodium peroxide may be employed with other acids, such as boric acid, and may be used alone, as may sodium perborate which breaks down to yield the peroxide. Other agents include oxidizing materials such as permanganate and bichromate alone or in conjunction with sulfuric, oxalic, or other acids.

In the case of the chlorine-containing agents, the strength of the solution should not be below 0.1% available chlorine. Stronger solutions may be used, going up to or 10%, or higher. Whatever concentration is employed, it must be correlated with the treating time and the temperature. Thus, using sodium hypochlorite, it has been found that the hypochlorite has a two-fold effect on the fabric: it lowers the shrinkage. and it decreases the tensile strength. Example 7 shows the effect of hypochlorite concentration and treating time upon the tensile strength of a marquisette fabric at 25 C. Preferred treating temperatures range from room temperature to about 80 F., although higher or lower temperatures may be used. Treating periods may range from to 60 minutes. In the case of hypochlorite, for example. illustrative operating conditions would be as follows (see Example 7) temperature, C.; treating time, minutes; available chlorine concentration, 0.1 to 2.3%.

In applying the hypochlorite degradation agent to the cloth, the latter is maintained in an unstretched condition and may be impregnated with a solution of the agent or immersed therein. When immersion is employed, the cloth may be agitated in the solution. The cloth may then be washed, and thereafter it is carefully dried and framed.

The next step in the treatment of the cloth according to this modification is the application of the caustic zincate-urea solution, which, to a notable degree, serves to stabilize the cloth against against shrinkage, as well as to clarify it. In applying this solution, the conditions to be employed are substantially the same as described above in connection with the single step process. The following example illustrates the variation in tensile strength with hypochlorite treating conditions obtainable by the two stage process:

Example 7 A series of runs were made in which marquisette cloth (unstretched) in 3.5.gm. pieces were tumbled at 25 C. for 30 minutes in a number of sodium hypochlorite solutions ranging from below 0.1% available chlorine to about 5.4%. Another group of samples were subjected to identical treatment except that a treating time of 60 minutes was used. The goods were then washed with cold water, rinsed with 1% hydrosulfite solution (antichlor) and then water again. Each sample was dried at 220 F. for about two minutes, framed, and saturated with the caustic zincate-urea solution (4.5% zinc oxide, 10% caustic, and 10% urea). Each was then placed in a current of hot air until the material felt just dry, rinsed in water at about 100 F., washed with cold 5% acetic acid, and finally with water until neutral. The samples were then dried at about 220 F. and removed from the stretching frame. Tensile strengths of the samples were determined according to the procedure above indicated. Following are the results:

These figures are based upon the tensile strength as measured at the conclusion of the overall process, and therefore include any change due to the caustic zincate-urea solution.

The concentrations of the other degradation agents will, of course, be different from those obtaining in the case of hypochlorite, and will also vary among themselves, depending upon the agent and the particular treating conditions employed. Therefore no general numerical range covering them collectively can be given in terms of concentration, but for all of them the concentration must be such as not to effect an excessive overall loss in tensile strength. Such concentrations, as indicated, will vary with the temperature and the time of treatment, lower concentrations being suitable with longer times and higher temperatures, and vice versa. Conditions suitable for use with these degradation agents may be found in Example 9 below.

In a second modification of the solution treating process, the cloth is given a chemical degradation, then treated with the solution, and finally treated with a special stiffening liquor. By this process a greatly increased stiffness is imparted to the cloth, in addition to the stabilization and clarification effects which result from the degradation and solution treating steps. The overall result of this modified or three stage process is more than merely the added effect of the stiffening liquor, for it has been found, as shown below, that the loss in tensile strength incurred by the first two stages of the process is reduced in the third stage, i. e., the fabric gains strength by treatment with the stiffening liquor. Moreover, as pointed out in Example 2, the step of drying the solution on the cloth resulted in better stiffness. In the three stage process. the use of the stiffening liquor affords the advantage of a greater stiffness effect and with increased stiffness there are also obtained improved clarification and shrinkage or dimensional stabilization effects.

In practicing the three stage process, the cloth i first subjected to the action of the degradation agent and then to the solution treating operation as described heretofore. It is then ready for the stiflening liquor. The latter may have a composition as follows: about 20 to 35% by weight of an alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide; about 2 to 6% by weight of zinc oxide; and about 8 to 12% by weight of urea. A preferred range for the sodium hydroxide is from about 20 to about 25%. For potassium, a range of from about 28 to about 35% is preferred. A preferred composition is: sodium hydroxide 22%, zinc oxide 4% and urea 10%.

Treating times with the stiffening liquor may vary from about ten seconds to about two minutes. Treating temperatures above and below room temperature may be used, although room I eat degradation agents upon the cloth with respect to tensile strength, stillness, and shrinkage. Samples of cotton marquisette that had been conventionally kier boiled and which had temperature is preferred. The liquor is applied 5 the following characteristics were used:

Breaking Strength Thread Count 1 1 3 G by I ylgeiilliltilely p r inc Pfiun ds. M i n. Mgslhelsnper 613! ax. Max.

Warp Filling Warp Filling to the fabric in any desired manner while the Samples of this marquisette were treated with latter is under tension, or not, as desired. different degradation agents at normal treating The following'example illustrates the s'trengthconditions for each agent. Then the loss in tenening effect of the stiffening solution; 20 sile strength of each sample was measured. Fol- E a le 8 lowing this, each sample was subjected to the x mp solution treating step comprisin a 1- to 2-min- Marquisette that d n i r le w s cut ute treatment at C. with a solution containinto a number of 14" x 20" pieces and these were ing 10% caustic, 4.5% zinc oxide, and 10% urea. subjected to degradation treatments by tumbling 25 The solution was washed from the sample b for 60 minutes at 25 C. in o i m ypochlorite fore drying the same. The usual souring, washsolutions ranging from 0.1 to 5.4% available ing. drying and framing conditions were obchlorine. After the usual rinsin the samples served. Thereafter, each sample was treated were dried at 220 F. for about two minutes. with a stiilening liquor containing 22% caustic, They were then framed to original width and 4% zinc oxide, and 10% urea, for one to two treated for one minute with the caustic zincateminutes at 25 0., again observing the usual auxurea solution (10% caustic. 4.5% zinc oxide, 10% iliary operations. Results of these treatments urea) at 25 C. Thereafter they were rinsed areasfollows:

Loss in Tensile Shrinkage,

Strength stmness' Per Cent Sample A Mm gggg g I er 0 1 1118. F- Degmi rvtecrgsls Warp lllmg Original Cloth 0.05 12 2) Original Cloth. starched 10,1 18.1 Degraded Cloth (Degrading agent and conditions):

NaOCl (1.25% available 012) 60 min. 25 0 2e 1e .21 3.5 5.2 KMnOl (1%)111 also. 2%) 1 min.

at25C 26 28.5 .38 5.0 2.6 KMnOl (1%) in NazCO; 2%) 0.5

min. at250 25.5 s2 .38 4.6 2.8 mso. 15min. at 25" o 19 a) .28 as 4.1

Figures enclosed in parentheses refer to concentrations.

with water, 5% acetic acid, and water again, and dried at 220 F. for two minutes. They were then framed, given a one-minute treatment with the stiffening liquor (22% caustic, 4% zinc oxide, 10% urea) at 25 C., rinsed and dried as before. Tensile strength data, measured as described, are as follows:

Loss in Tensile Strength, Per Cent Available Chlorine, Per Cent After After Degradation Overall Stage Process 0.1 4. 0 0. 2 0.5 11.3 v 6. 8 1. 0 16. 0 11. 6 1. 6 18. 9 l4: 5 2.0 21. 0 l6. 5 2. 5 22. 4 17.8 3. 0 23. 7 l8. 5 3. 5 24. 8 18.9 4. 0 25. 8 19. 3 4. 5 26. 6 19. 6 5. 4 27. 5 19.6

Example 9 In this example is shownthe effect 01' diiler- It will be observed that in the case of the hypochlorite, subsequent treatment with the solution and the stiifening liquor served to reduce the loss in tensile strength. Tensile strength, stiffness, and shrinkage were determined according to methods heretofore described. The data on stifl'ness and shrinkage were obtained at the conclusion of the overall process.

Example 10 ample 8. This sample and a cotton marquisette of the same construction but finished according to the'commerci'al sulfuric acid method were then tested, the shrinkage and stillness data on the former being reported as at the end of the overall process.

* After plant treatment. Finished cloth.

As will be seen, the present process yielded a cloth of superior shrinkage quality, while the stifiness results are of the same order as commercial samples which are noted for their stiffness qualities.

Besides the foregoing processes involving one, two, and three stages, useful effects may be attained by various alternative processes in which the sequence of operations may be as follows: (1) degrade-apply stiffening liquor-apply solution-apply stiffening liquor, or (2)degrade-apply solution-apply stiffening liquor-appiy solution. In still other alternative methods. the degradation step of the last-mentioned sequences may be omitted, thus offering advantages in time and material saved, although the results. while satisfactory for some purposes, may not be as good as those to be obtained in the one, two and three stage processes described above in detail.

Example 11 Samples of the same leno weave cotton marquisette used in Example 3 were held under moderate tension on a frame and treated at room temperature with various solutions in which sodium hydroxide and sodium zincate had been replaced by potassium hydroxide and potassium zincate. The treatment of the samples was carried out in the manner described in Example 3. Amounts of potassium hydroxide corresponding to the minimum, preferred and maximum concentrations of sodium hydroxide were used. Samples treated with the minimum, preferred and maximum compositions of sodium hydroxide, zinc oxide and urea were included for comparison. The results are as follows:

Solution Composition, Per

Cent 5mm Tensile Stiffness Strength Coeffi- Warp cient KOH NaOH ZnO Urea Warp Filling Pounds 6 2 2 9.0 12.0 22. 2 406 8.4 2 2 7.- l0.4 24.6 .26 2 2 7. 3 9. 3 25. 4 50 16.8 6 10 4.0 6.3 8.9 .72 o 10 4.0 7.8 DJ; 3.76 10 1) 4.1 7.8 21.1 LN 10 6.5 8.3 30.9 1.34 10 20 5.1 6.7 24.3 1432 In conclusion, it is to be noted that in place of urea per se or the urea forming compounds as described, other compounds may be employed as one of the components in the present treating solution as, for examples, the alkali metal thiocyanates; sodium thiocyanate, potassium thiocyanate or ammonium thiocyanate. and the polyamines; ethylene diamine or hexamethylenetetramine.

This application is a continuation in part of copending application Serial Number 616,451, filed September 14, 1945 now abandoned.

What is claimed is:

1. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, drying the treated fabric while under tension, neutralizing the same and thereafter rinsing the fabric.

2. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate. selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about '1 second to about 24 hours, drying the treated fabric while under tension and neutralizing the same.

3. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water. for a time ranging from about 1 second to about 24 hours, drying the treated fabric while under tension and thereafter washing the solution therefrom.

4. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours. drying the treated fabric and thereafter neutralizing and rinsing the same.

5. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea. an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time rangin from about 1 second to about 24 hours, drying the treated fabric and thereafter neutralizing the same.

6. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, andthe balance water, for a time ranging from about 1 second to about 24 hours, drying the treated fabric and then washing the solution therefrom.

7. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, neutralizing the treated fabric and rinsing the same.

8. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 toabout 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and thereafter neutralizing the treated fabric.

9. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and then washing the solution from the treated fabric.

10. Method of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, sodium zincate equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 20% by weight of sodium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours and subsequently removing the solution from the treated fabric.

11. Method of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, potassium zincate equivalent to from about 2 to about 10% by weight of zinc oxide, from about 8 to about 28% by weight of potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours and subsequently removing the solution from the treated fabric.

12. Method of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, sodium zincate equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of sodium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and subsequently removing the solution from the treated fabric.

13. Method of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, potassium zincate equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours and subsequently removing the solution from the treated fabric.

14. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and subsequently removing the solution from the treated fabric.

15. Process of modifying the characteristics of cotton fabric which includes the step of sub- Jecting said fabric in an unstretched condition to the action of an oxidizing agent to obtain a partial degradation of the fabric, and thereafter treating the partially degraded fabric with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amountequivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and subsequently removing the solution from the fabric.

16. Process of modifying the characteristics of cotton fabric which includes the steps of subjecting said fabric in an unstretched condition to the action of an oxidizing agent to obtain a partial degradation of the fabric, and thereafter treating the partially degraded fabric with an aqueous solution comprising from about 2 to about 20% by weight of urea, sodium zincate in an amount equivalent to from about 2 to about 10% by weight of zinc oxide, from about 6 to about 20% by weight of sodium hydroxide, and the balance water, for a time ranging from about 1 second to about 24 hours, and subsequently removing the solution from the fabric.

1'7. Process of modifying cotton fabric which includes the steps of subjecting said fabric in an unstretched condition to the action of an oxidizing agent to obtain a partial degradation of the fabric, treating said partially degraded fabric with an aqueous solution comprising from about 2 to about 20% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate equivalent to from about 2 to about 10% by weight of zinc oxide, and from about 6 to about 28% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, for a time ranging from about i second to about 24 hours, removing the solution from the fabric and thereaftersubiecting the partially degraded and treated fabric to the action of an aqueous stiifening liquor comprising from about 8 to about 12% by weight of urea. an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate in an amount equivalent to from about 2 to about 6% by weight of zinc oxide and from about 20 to about 35% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassiumhydroxide, and removing the stiffening liquor from the fabric.

18. Process of modifying cotton fabric which includes the steps of subjecting the fabric in an unstretched condition to the action of an oxidizing agent to obtain a partial degradation of the fabric, treating said partially degraded fabric with an aqueous solution comprising from about 2 to about 20% by weight of urea, sodium zincate equivalent to from about 2 to about by weight of zinc oxide, and from about 8 to about 20% by weight of sodium hydroxide, for a time ranging from about 1 second to about 24 hours, removing the solution from the fabric, and thereafter subjecting the partially degraded and treated fabric to the action of an aqueous stiffening liquor comprising from about 8 to about 12% by weight of urea. sodium zincate in an amount equivalent to from about 2 to about 8% by weight of zinc oxide, and from about 20. to about 25% by weight of the stiffening liquor from the fabric.

19. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising about 10 per cent by weight of urea. sodium zincate. in an amount equivalent to about 6 per cent by weight of zinc oxide, about 12 per cent by weight of sodium sodium hydroxide.- .and removing.

hydroxide and the balance water, for a time of about one minute, drying the treated fabric under tension, and subsequently neutralizing, rinsing, and drying the fabric.

20. Process of modifying cotton fabric which includes the steps of treating the same with an aqueous solution comprising about 10 per cent by weight of urea, sodium zincate in an amount equivalent to about 6 per cent by weight of zinc oxide, about 12 per cent by weight of sodium hydroxide and the balance water, for a time of about one minute, drying the treated fabric under tension, subsequently neutralizing and rinsing the fabric in an unstretched condition, and finally drying the fabric under tension.

CHARLES L. MANTELL.

OSCAR K. HEIM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,630,365 Weber May 31, 1927 1,661,879 DeGoncz Mar. 6, 1928 2,129,708 Bchreiber Sept. 13, 1938 2,142,043 Boyd Dec. 27, 1938 2,203,375 Weiss June 4, 1940 FOREIGN PATENTS Number Country Date 20,814 Great Britain 1889 266,466 Great Britain Feb. 24, 1927 516,843 Great Britain Jan. 12, 1940 OTHER REFERENCES Kata et al., Rayon Text. Mo., Dec. 1940, pages 

1. PROCESS OF MODIFYING COTTON FABRIC WHICH INCLUDES THE STEPS OF TREATING THE SAME WITH AN AQUEOUS SOLUTION COMPRISING FROM ABOUT 2 TO ABOUT 20% BY WEIGHT OF UREA, AN ALKALI METAL ZINCATE SELECTED FROM THE CLASS CONSISTING OF SODIUM ZINCATE AND POTASSIUM ZINCATE IN AN AMOUNT EQUIVALENT TO FROM ABOUT 2 TO ABOUT 10% BY WEIGHT OF ZINC OXIDE, FROM ABOUT 6 TO ABOUT 28% BY WEIGHT OF ALKALI METAL HYDROXIDE SELECTED FROM THE CLASS CONSISTING OF SODIUM HYDROXIDE AND POTASSIUM HYDROXIDE, AND THE BALANCE WATER, FOR A TIME RANGING FROM ABOUT 1 SECOND TO ABOUT 24 HOURS, DRYING THE TREATED FABRIC WHILE UNDER TENSION, NEUTRALIZING THE SAME AND THEREAFTER RINSING THE FABRIC. 